Separator



Sept. 24, 1963 E. P. TROLAND SEPARATOR Filed March 14. 1960 UnitedStates Patent 3,105,044 SEPARATOR Edwin P. Troland, Hingham, Mass,assignor to Bird Machine Company, South Walpole, Mass, :1 corporation ofMassachusetts Filed Mar. 14, 1960, Ser- No. 14,699 3 Claims. (til.210-512) This invention relates to apparatus for separating solidparticles and gas bubbles from a liquid suspension and pertains morespecifically to a cyclone-type separator adapted to purify paper pulp.

Cyclone-type separators have been proposed for purifying paper pulp andhave been found to be highly effective for the removal of dirtparticles, shives, and the like from the aqueous pulp dispersion. Whenoperated with the restricted outlet discharging rejected particlesfreely to the atmosphere, however, it is impossible to remove air orother gas bubbles from the pulp even though it would e expected that thebubbles would migrate to the central hollow vortex of the liquid whichis produced in such devices during operation. It appears that anybubbles which do migrate to the hollow vortex are again intermingledwith the liquid dispersion as the latter leaves the device through themain outlet for the purified dispersion. Indeed, additional air isfrequently drawn in through the restricted outlet of such a device andintermingled with the liquid suspension so that the device not onlyfails to removebubbles but actually introduces additional bubbles.Although it has been proposed to employ a suction pump to remove gasesfrom within the hollow vortex through a separate pipe or tube or to havethe restricted outlet of the device discharge into an evacuated chamberin order to remove gas bubbles as well as dirt from the dispersion, suchexpedients add substantially to the cost of installation and operationof the device.

One object of the present invention is to provide a cyclone-typeseparator of simple and inexpensive construction adapted to purify paperpulp by removing from it both gas bubbles and dirt particles.

Another object is to provide a separator of the type described which canbe operated with its restricted outlet discharging continuously at anypressure, even above atmospheric pressure, without the need for anysuction pump or similar pressure-reducing means for removing the gas.

Other and further objects will be apparent from the drawing and from thedescription which follows.

In the drawing:

FIG. 1 is a view in side elevation, partly broken away and in section,showing one embodiment of the present invention;

FIG. 2 is a view in cross section taken along line 22 of FIG. 1;

FIG. 3 is a view in vertical section on an enlarged scale, partly brokenaway, showing another embodiment of the invention;

FIG. 4 is a view in cross section taken along line 4-4 of FIG. 3; and 7FIG. is a view in vertical section, partly broken away, showing still athird embodiment of the invention.

()ne of the preferred embodiments of the present invention asillustrated in FIGS. 1 and 2 of the drawing includes an elongatedchamber 1% of circular cross-sectional configuration tapering indiameter as shown at 12 adjacent one end where it terminates in acentrally located restricted orifice or outlet 14. At the other end ofthe chamber 10, an inlet 16 is provided arranged tangentially to thechamber, as best appears in FIG. 2 of the drawing. A second or mainoutlet 18 in the form of a tubular discharge member is disposedcentrally of the chamber ad jacent the same end as that at which inlet16 is located.

Outlet 18 is tubular in form, having a cylindrical wall which extendsinto the chamber and terminates in an open end 2% disposed beyond inlet16 along the axis of the chamber in the direction of restricted outlet14.

Mounted on a cross bar or spider 22 secured within outlet 13 is aprojecting core'element 2,4 which is located centrally of tubular outlet18 and which has a smooth end face 26 flush with the open end 20,forming together with the tubular member an annular outlet.

In operation of this embodiment, the paper pulp dispersion containingdirt particles and bubbles of air or other gas is introduced underpressure through inlet 16, the stream of pulp dispersion progressing inspiral fashion along the length of chamber 10 toward restricted outlet14. As the rapidly rotating mass of liquid dispersion advances spirallythrough chamber 10, it is turned back upon itself at some point in thetapering portion 12 of the chamber and forms an inner annular layer ofpulp dispersion progressing through chamber 10 toward the main outlet13. Because of the high gravitational forces developed within therapidly rotating mass of liquid, a hollow vortex or core 23 is formed,as indicated by dotted lines. This hollow vortex is normally continuousto the restricted outlet 14 and is continuously in communication withthe ambient atmosphere through this outlet, although it may be operatedsuccessfully with outlet 14 discharging at either elevated or reducedpressure.

The precise diameter of hollow vortex 28 will depend upon the rotationalspeed of the liquid mass within the chamber (which in turn is dependentupon the overall dimensions of the device and the pressure drop throughit, which is usually 40 to 60 p.s.i.), the pressure of the atmospherewith which the hollow vortex is in communication through restrictedoutlet 14, and the diameter of the periphery of tubular outlet or vortexfinder 18. By proportioning the diameter of core element 24 so that itis somewhat greater than the diameter of hollow vortex 28, preferablyabout 10% to 26% greater, it is found that bubbles of air or other gaswhich migrate to the hollow vortex of the spinning mass of liquid pulpdispersion are obstructed and prevented from becoming redispersed in theliquid as it leaves the device through outlet 18. Instead, as the air orgas bubbles accumulate within hollow vortex 23, any excess gas is freelyvented to the atmosphere through restricted outlet 14.

It is not essential that the end 26 of core element 24 be perfectlyflat, but it is preferably smooth in order to minimize the possibilityof producing turbulence which would result in the gas bubbles becomingentrapped or entrained again within the pulp dispersion as it proceedsthrough outlet 18.

The length of core element 24 and the position Within tubular outlet 18of spider 22 are not critical. The position of spider 22, for example,may be varied from the region of the open end 20 of tubular outlet 18 toa position several inches removed from the open end. The spider must besturdy enough to support core element 24 securely while at the same timebeing slender enough to avoid excessive obstruction of the flow ofdispersion through outlet 18.

in another embodiment, as illustrated in FIGS. 3 and 4, the upper partof chamber 10 (the lower part'is identical with that of FIG. 1) isprovided with an annular flange 30 to which is bolted a unitary casthead 32 which includes a centrally located main outlet 36 in the form ofa tubular discharge member the peripheral wall of which converges towardan open end 38. Outlet 36 also converges outside of chamber 10 to abolting flangeA-t which serves to secure the device to a main outletpipe 42 for accepted stock.

Mounted within outlet 36 is a cross bar or spider 44 which serves tosupport a core element 46 disposed cen:

ale-5,044

3 trally of outlet 36 and extending along the axis of outlet 36 towardopen end 38. Core element 46 is provided with a tapped opening in itsterminal face adapted to receive a threaded projection on a supplementalcore element 48. Supplemental core element 48 is not of uniform diameteras is core element as, but increases gradually in diameter beyond openend 38, terminating in a smooth, circular, gently rounded face 54Terminal face 59 in this embodiment preferably is disposed beyond openend 38 along the axis of the chamber toward re stricted outlet 14 by adistance at least equal to the diameter of the open end.

Because of the projection of core element 48 Within chamber 10 beyondthe open end 38 of the main outlet, it is possible to make thevortex-obstructing face 5% of considerably greater diameter than coreelement do without reducing the flow capacity of the annular passagewayat open end 38. This additional diameter of terminal face 59 providesadditional insurance against the possibility that hollow vortex 28, theposition of which changes slightly and erratically under ordinaryoperating conditions, might extend beyond the margin of obstructing face50 and permit some of the gas contained within it to be entrained in theliquid dispersion as it exits from chamber 1%) through open end 38 ofthe main outlet. In a preferred embodiment, core element as has adiameter from to 20% greater than that of the hollow vortex Within theliquid during operation of the device while obstructing face 50 has adiameter from to 109% greater than that of the hollow vortex. Thediameter of the core and of face 59 cannot exceed about 50% of theadjacent inner diameter of chamber 16 without seriously impairing theeflioiency and effectiveness of the separating function of theapparatus. For the same reason, the obstructing face 54) as well as coreelement 48 cannot be supported from the Wall of chamber to by a spideror by brackets, which disturb the flow pattern of the liquid dispersion,but are supported from the interior of the main outlet, just as in thecase of the embodiment shown in FIG. 1 of the drawing.

If the length of core element 48 is very great, so that terminalobstructing face 5% is spaced from open end 38 by a distance greaterthan about four times the diameter of the open end, it is found that theair or gas bubbles tend to migrate to the center before the enteringstream of liquid dispersion feed passes beyond terminal face 56.Consequently, these bubbles strike the cylindrical side wall of coreelement 48 and are carried along it through open end 38 by the acceptedpulp dispersion which is leaving the device. The preferred position forthe obstructing face 5!) of the embodiment shown in FIG. 3 isaccordingly in a zone extending from the open end of the main outletalong the axis of the chamber toward the restricted outlet at a distancefrom the open end ranging from one to. four diameters of the open end ofthe main outlet.

The supporting spider 44 is preferably spaced from open end 38 by adistance at least equal to the diameter of the open end in order tominimize obstruction of the annular outlet passage. The increasingdiameter of tubular outlet 36 as the flow of accepted dispersionproceeds toward outlet .pipe 42 makes it possible to provide a verystrong and rigid support for the core element Without reducing theeffective capacity of the outlet.

In a third embodiment of the invention, as shown in FIG. 5, tubulardischarge member or outlet 64} is flared outwardly adjacent its open end62, and is provided with a core element 64- mounted on a supportingcross bar as and terminating in a smooth circular face 68 which isdisposed within outlet 6%} spaced from its open end.

This embodiment is somewhat less effective than the embodiments of FIGS.1 and 2 for removing dirt particles from the dispersion, but is somewhatmore effective for removing gas bubbles than are the other twoembodiments. It is found that the flaring wall of tubular outlet orvortex finder 69 tends to stabilize the hollow vortex 28, while therecessed position of the terminal obstructing face 68 ensures that all'of the bubbles which migrate toward the center of the rotating mass ofliquid have time to reach the vortex before being carried past face 63by the departing stream of pulp dispersion as it proceeds throughtubular outlet 69. Having once reached the hollow vortex, the bubblesare prevented from passing through with the accepted material by theobstructing face 63.

Although specific embodiments of the invention have been describedherein, it is not intended to limit the invention solely thereto, but toinclude all of the obvious variations and modifications within thespirit and scope of the appended claims.

What is claimed is:

1. Apparatus for separating solid particles and gas bubbles from aliquid suspension comprising a chamber having a substantially circularcross-section and a conical end portion, an inlet arranged tangentidlywith respect to said chamber adjacent one end thereof remote from theapex of said conical portion for introducing said suspension into saidapparatus to form a stream which initially passes spirally along thewall of said chamber toward the apex of the conical portion thereof andwhich reverses inwardly on itself before reaching said apex to form ahollow vortex, a firs-t outlet for rejected solids and gas at the apexof said conical portion in communication with said hollow vortex, asecond outlet for accepting suspension having its mouth disposedcentrally of said chamber between said inlet and said apex in positionto receive the reverse flow of liquid suspension from around sm'd hollowvortex, and an element mounted within said chamber having an obstructingface centrally aligned with respect to said month, said face beingdisposed between said inlet and said apex substantially in the plane ofthe mouth of the second outlet and having a diameter at least as greatas tne diameter of said vortex and less than the diameter of said mouthto block the passage of said vortex through said second outlet whilepermitting the liquid suspension to pass around the periphery of saidface.

2. Apparatus for separating solid particles and gas bubbles from aliquid suspension comprising a chamber having a substantially circularcross-section and a conical end portion, an inlet arranged tangentiallywith respect to said chamber adjacent one end thereof remote from theapex of said conical portion for introducing said suspension into saidapparatus to form a stream which initially passes spirally along thewall of said chamber toward the apex of the conical portion thereof andwhich reverses inwardly on itself before reaching said apex to form ahollow vortex, a first outlet for rejected solids and gas at the apex ofsaid conical portion in communication with said hollow vortex, a secondoutlet for accepting suspension having its mouth disposed centrally ofsaid chamber between said inlet and said apex in position to receive thereverse flow of liquid suspension from around said hollow vortex, saidsecond outlet converging in the direction of outlet flow from saidmouth, and an element mounted within said second outlet having anobstructing face centrally aligned with respect to said mouth, said facebeing disposed between said inlet and said apex within said secondoutlet in the plane of the minimum diameter thereof and having adiameter at least as great as the diameter of said vontex and less thansaid minimum diameter to block the passage of said vortex through saidsecond outlet while permitting the liquid suspension to pass around theperiphery of said face.

3. Apparatus for separating solid particles and gas bubbles from aliquid suspension comprising a chamber having a substantially circularcross-section and a conical end portion, an inlet arranged tangentiallywith respect to said chamber adjacent one end thereof remote from theapex of said conical portion for introducing said suspension into saidapparatus to form a stream which initially passes spirflly along thewall of said chamber toward the apex of the conical portion thereof andwhich reverses inwardly on itself before reaching said apex to form ahollow vortex, a first outlet for rejected solids and gas at the apex ofsaid conical portion in communication with said hollow vontex, a secondoutlet for accepting suspension having its mouth disposed centrally ofsaid chamber between said inlet and said apex in position to receive thereverse flow of liquid suspension from around said hollow vortex, and anobstruction element mounted within said second outlet and centrallyaligned with respect to said mouth, said element extending from withinsaid mouth to a point therebeyond to provide a vortex obstructingportion having a diameter at least as great as the diameter of saidvortex and not more than 50 percent of the adjacent inner diameter ofsaid chamber disposed between said mouth and a distance from said mouthof at most about four times the mouth diameter, said portion beingeffective to block passage of said vortex through said second outletWhile permitting the liquid to pass around the periphery thereof.

References Cited in the file of this patent UNITED STATES PATENTS2,566,662 Hill Sept. 4, 1951 2,757,581 Freeman et al. Aug. 7, 19562,816,490 Broadway et a1. Dec. 17, 1957 2,835,387 Fontein May 20, 19582,878,934 Tomlinson Mar. 24, 1959 FOREIGN PATENTS 740,588 Great BritainNov. 16, 1955 523,316 Canada Mar. 27, 1956

1. APPARATUS FOR SEPARATING SOLID PARTICLES AND GAS BUBBLES FROM ALIQUID SUSPENSION COMPRISING A CHAMBER HAVING A SUBSTANTIALLY CIRCULARCROSS-SECTION AND A VONICAL END PORTION, AN INLET ARRANGED TANGENTIALLYWITH RESPECT TO SAID CHAMBER ADJACENT ON END THEREOF REMOTE FROM THEAPEX OF SAID CONICAL PORTION FOR INTRODUCING SAID SUSPENSION INTO SAIDAPPARATUS TO FORM A STREAM WHICH INITIALLY PASSES SPIRALLY ALONG THEWALL OF SAID CHAMBER TOWARD THE APEX OF THE CONICAL PORTION THEREOF ANDWHICH REVERSES INWARDLY ON ITSELF BEFORE REACHING SAID APEX TO FORM AHOLLOW VORTEX, A FIRST OUTLET FOR REJECTED SOLIDS AND GAS AT THE APEX OFSAID CONICAL PORTION IN COMMUNICATION WITH SAID HOLLOW VORTEX, A SECONDOUTLET FOR ACCEPTING SUSPENSION HAVING ITS MOUTH DISPOSED CENTRALLY OFSAID CHAMBER BETWEEN SAID INLET AND SAID APEX IN POSITION TO RECEIVE THEREVERSE FLOW OF LIQUID SUSPENSION FROM AROUND SAID HOLLOW VORTEX, AND ANELEMENT MOUNTED WITHIN SAID CHAMBER HAVING AN OBSTRUCTING FACE CENTRALLYALIGNED WITH RESPECT TO SAID MOUTH, SAID FACE BEING DISPOSED BETWEENSAID INLET AND SAID APEX SUBSTANTIALLY IN THE PLANE OF THE MOUTH OF THESECOND OUTLET AND HAVING A DIAMETER AT LEAST AS GREAT AS THE DIAMETER OFSAID VORTEX AND LESS THAN THE DIAMETER OF SAID MOUTH TO BLOCK THEPASSAGE OF SAID VORTEX THROUGH SAID SECOND OUTLET WHILE PERMITTING THELIQUID SUSPENSION TO PASS AROUND THE PERIPHERY OF SAID FACE.